1. Field of the Invention
The present invention relates to a computer controlled positioning table for use in automatically rotating a large article into which an evenly spaced circle of bolt holes are to be drilled. The article to be drilled is centered on a table top of the table and then the computer rotates the table top incrementally to precisely position the article relative to an associated stationary drill stand to be used in drilling the desired holes in the article. Once the table top has rotated to the proper position, locking mechanism hold the table top in position while a hole is drilled in the article by the associated drill stand. Rotation of the table top is computer controlled, allowing the operator to select the number of bolt holes for each article. The present invention allows the operator to quickly and repeatedly create articles with evenly spaced bolt holes or any other desired spacing of bolt holes accurately located to within very close tolerances.
2. Description of the Related Art
Smaller articles that need to have a plurality of evenly spaced holes drilled can be fairly easily and accurately drilled with currently available equipment. Smaller articles, i.e. those articles having outside diameters (OD) of up to approximately 100 inches, can be placed on an automated drill table in order to drill evenly spaced holes in the article. One such automated drill table which includes preprogrammed bolt spacing was produced by Babin since approximately the 1950's. This automated drill table has the drawback that the number of bolt spacing was preprogrammed and therefore limited to approximately twenty different spacings. It was not useful if a different number or spacing of bolt holes was desired or needed.
However, larger articles, such as ones of an OD exceeding 100 inches and up to approximately 182 inches in OD still must be manually laid out and then drilled. These large articles generally are heavy, i.e. weighing up to 20,000 pounds, and are difficult to handle. Manually laying out the spacing of the holes involves first scribing a circle on which each of the holes is to be centered, and then using a divider to mark the individual spacing for the desired number of holes. This process is time consuming and inaccurate. Also, once the center for each hole has been marked, then either the drill or the article or both must be manually positioned to try to place the drill bit precisely centered on the center mark for each hole. This process, even if conducted by highly skilled and experienced workman, will normally result in an article having hole spacing that are not within close tolerances. Tolerances in excess of 1/32 inch are generally unacceptable.
The present invention addresses this problem by providing a computer controlled positioning table that can be used to automatically rotate a large article into which an evenly spaced circle of bolt holes are to be drilled. The present invention can be used on articles up to approximately 182 inches in OD and can bear a balance load of approximately 20,000 pounds. The article to be drilled is centered on a table top of the table and then the computer rotates the table top incrementally to precisely position the article relative to an associated stationary drill stand to be used in drilling the desired holes in the article.
Once the table top has rotated to the proper position, a variety of locking mechanisms hold the table top in position while a hole is drilled in the article by the associated drill stand. The outside portion of the table top is provided with additional support and locking capability by way of support rollers with locking mechanisms to prevent the table top and the attached article from tipping or otherwise moving while the holes are being drilled. Because rotation of the table top is computer controlled, the number of bolt holes can be selected for each article and the location of the bolt holes can be precisely controlled by moving only the table top relative to a stationary drill stand. The present invention allows the operator to quickly and repeatedly create articles with evenly spaced bolt holes accurately located to within very close tolerance.